Method of electric riveting



Nov. 13, w28.

F. P. KOBERT METHOD OF ELECTRIC RIVETING originai Filed Jan. 22. 19:21=

14@ ze 14g-5 Patented Nov. 1928.

lUNITED STATES FRANK P. KOBEBT,.QF AMITYVILLE, NEW YORK.

METHOD QF ELECTRIC BIVETING.

Application tiled vIanuaryp, 1921, Serial No. `439,1@1 Renewedk Harsh28, 1998. l l

My present invention relates to methods and means for fabricating metalarticles and to the resulting products. In particular, my inventionrelates to methods and means 5 for assembling or fabricating metalarticles,

as by riveting, for example, in such a manner that the articles producedbymy invention are much more economically and expeditiously manufacturedand in a much suerior form land condition than hitherto. referably theheating operation, or operations, where required in accordance with myinvention, are carried out by electrically heating the desired portionsof the metal, l5 preferably locally, as more fully set forthhereinafter. It is an ob'ect of the present invention to provide met odsand means of the general character indicated above whereby thefabrication and assembling of metal articles are rendered moreconvenient .and more rapid than before and articles of much su eriorquality produced.

n lthe accompanying specification I shall describe several illustrativeembodiments of 4 25 the method, means landproduct of the presentinvention, it being clearly understood, however, that my invention isnot limited to the illustrative embodiments thereof which are herein setforth for purposes of illustration only.

Referring to the drawings wherein I have diagrammaticall illustrated anillustrative embodiment of the process of my present invention. and alsodiagrammatically illustrated an illustrative embodiment of the apparatusof my present invention, and wherein I have also shown an illustrativeembodiment of an article comprising one formvof the product of mypresent invention:

Figure 1 is a plan view of a metal piece, comprising in this instance aside-piece for a pin for a roller chain .for chain-drives, this metalpiece forming one part of the metal article to be fabricated orassembled in accordance with the present invention;

.Figure 1 is a view similar to Figure 1 of a side-piece, theperforations of which are provided with slots so that the rivets will bekeyed in the perforations when the article is completed; y

Figure 1b is a side elevation of the two rivets Awhich are to becombined with the side-piece shown in Figure 1 or Figure 1'* for thefabrication of the illustrative article herein shown and described;`

55 Figure 2 is a side elevation artl in secu a P tion, of the two rivetsassembled in the sidepiece shown in ,Figure 1';

1 Figure 3 is a somewhat diagrammatic view of the riveting or otherfabricating or assembling device before the heating is commenced;

Figure 4 is a similar view of this device during the heating operation;

Figure 5 is a similar view ofthis device during the heading operation;

Figure 6 is a similar view of this device after .the heating and headingoperations have been completed; and

Figure 7 is a lon itudinal sectional view of the completed artie.

Referring to the illustrative embodiment of the article shown in theaccompanying drawings, it may be desirable to point out,

in this particular instance, the disadvantages of the procedures andproducts of the rior art, and the remedies for lthese dis vantagesafforded by the resent invention. In making pins for ro 1er chains forchainclrives, to be used in connection with automobile trucks andsimilar devices, it has been customary, hitherto, to use a side-pieceprovided with a plurality, as two, perforations. in which are positioneda plurality of unheaded rivets generally consisting of casehardenednickel steel. It has not been possible, hitherto, to hot forge the headsof the rivets into the side-pieces, since such au operation, as hithertocarried out, would inevitably result in the annealing of the riv- .etsand in thus drawin their temper .and

making them wholly un t for use. This is particularly so since, withtheV use of the case-hardened nickel steel rivets commonly employed inthis art, the'temper would be drawn at as low as 350 F., and surely at520 F. After annealing -the head of the rivet to make the rivetingoperation possible, it has hitherto been necessary to annealr said headby grindin the'sare on an emery or other friction w eel, or to annealtheV same by a heat treatment, as by means of a flame. The rivets arenow headed, asby cold hammering or by s inning.

The disadvantages of) this mode of operation/are obvious. Not only isthis operationlaborious and/tedious, requiring much hand labor andexpensive equipment, but

the operation itself is Avery expensive and slow, and the product, ,forthese reasons,

very costly. Furthermore, by the procedure hitherto followed in the art,it has not been feasible to key the rivets in the sidepieces. Theproducts of the prior art are, moreover, very inferior, lthe rivetsturning in the side-pieces after slight wear, and thus introducingfriction into the drive, and consequently rendering this from of drivecomparatively inefficient. Furthermore, the heads of the rivets wearloose and the lchain is veasily broken. These various factors are, to aconsiderable extent, responsible for the waning popularity of thechain-drive'.

y my invention these disadvantages and defects are to a very largeextent, and, in many cases, almost entirely, overcome. In practicing the`above-mentioned illustrative embodiments'of my invention, I take asidepiece 10 of the usual form, provided with perforations 11, as shownin Figure 1. 0r,

and preferably, especially where the rivets are desired to be, keyed inthe side-piece, I take a side-piece 12, as shown in Figure la, providedwith perforations 13, which perforations are in turn provided with theslots 14. rIhe side-pieces 10 and 12 may be of ordinary soft steel. y

I next provide a plurality of rivets 15 of a proper size to tit snuglyinto the perforations 14. Preferably these rivets are of steel, such asnickel steel, which may be case-hardened. The rivets 15 are nowassembled in theside-piece 12, as more particularly shownin Figure 2 ofthe drawing.

While various arrangements and' means for carryingj out the requisiteheating operations may e employed, I prefer to electrically heat therivets locally, adjacent their heads, by the means somewhatdiagrammatically illustrated in Figures 3 to 6, inclusive, of thedrawing. Such means comprises a plurality of supporting arms 16, each ofwhich carries an electrode 17, preferably of copper, which isreciprocatable in the supportin arm 16. Each arm 16 also carries a heaer 18, preferably of steel. The arrangement of arms 16, electrodes 17and Vheaders 18 is such that the electrodes can be brin the headersquickly into contact with the eated heads of the rivets to head thesame.

As a gig or supporting means for the pins during the assembling orriveting operation, I provide any suitable support 19 for suitablypositioning the assembled side-piece and rivets. Preferably, means areprovided for cooling the Shanks of the rivets during the heatin andheadi-no' operations. For this purpose I prefer to place the support 19,carrying the assembled side-piece and rivets, within a receptacle orother work-holder 2O having an inlet21 for the water, or other coolingmedium, and a regulatable over-flow 22 for the spent or Waste water. Bymeans of the regulatable overlow 22, the level of the cooling medium inthe holder 2O may be regulated at will so as to -maintain the levelsubstantially at the point shown in Figures 3 to 6 of the drawing.

The assembling or riveting operation is substantially as follows: lViththe electrodes and headers, and 'the article to be assembled orfabricated, in the positions shown in Figure 3, the electrodes 17 arereciprocated, as by being depressed, so as to be brought into contactwith the respective heads 15 of the rivets 15. The electrodes 17 aresuitably connected lto a source of heating current. Accordingly, uponContact being established .between the eectrodes and the respectiverivets and in so much only of the rivets as.

is slightly above the surface of the sidepiece and contained in theperforations 13,

ut practically not at all in the Shanks of the rivets.

This localized heating of the heads of the rivets, which may beaccomplished in about two seconds, heats the rivets to a temperature ofincandescence, tothereby enable the heads of the rivets to be readilyheaded in the subsequent operation of the device. By the highlocalization of the heatin current, substantially no heating ofthe xankso the rivets takes place. Furthermore, by means of the contact betweenthe cooling medium V23 in the work-holder 20 and the Shanks of therivet-s 15,these shanks are not permitted to be heated to a temperaturewhich would anneal them and thus deprive them of their temper.

The electrodes 17 are now reciprocated out of contact with the heads ofthe rivets when such heads have been heated to the desired temperature,and the arms 16 carrying the electrodes 17 and the headers 18 are nowswung, or otherwise moved, to brine' the headers very quickly into theposition siown in Figure 5 of the drawings, in which position theheaders act to head the rivets and to thus hot forge and key the headsof the rivets in the slotted perforations 13 of the side-piece 12.Preferably the heading operation takes place within a fraction, asoneeration takes place without any substantial ypor undesirable heatingof the shanks of the aivets and without in any Wav annealing and drawingthe temper of the shanks of the rivets.

The supporting arms 16 are now operated to brinfr the headers out ofcontact with the headed rivets, and these arms are swung, or otherwisemanipulated, to bring them back int'othe position shown in Figure 3 ofthe drawing, `in which position they are ready to repeat the series ofoperations described above on another assembled sidepiece and rivets.'

The advantages of the foregoing illustrative embodiments of lnyinvention are numerous and of great importance.I By means of my presentinvention the pins are perfectly riveted and the shanks of the pinsmaintain their initial degree of hardness unimpaired. By means of thepresent invention, also, the heads of the rivets are not only hot for edinto the perforations in the side-pieces, gut may also be keved in thesame operation of hot forging. r:The shanks of the rivets areuna-nnealed and retain their original temper unimpaired. This highlydesirable condition results from the fact that the heatin of the headsof the rivets is almost comp etely localized and from the further fa'ctthat the heads are formedand the heat dissipated before any annealingeffect can take place in the shanks of the rivets.

The cooling means for the shanks of the rivets further assists inbringing about this hi hly desirable effect.

he foregoing invention can be applied with equal success to a Widevariety of metal articles of manufacture, since it can be used forforging the heads of bolts and screws into devices of very many types.As another example of a class of articles to which the present inventionmay be applied with great success, I may mention the manufacture ofcap-screws.

It is of course to be understood that my invention is not limited to theparticular embodiment thereof which are herein described for purposesofillustration only.

What-,I claim is:

1. The method of assemblin metal articles by electric riveting whiccomprises positioning a plurality of metal rivets in a metalpiece,passing electric current through the heads ot' said rivets andthrough said piece so as to heat said heads locally Withoutsubstantially. heating the shanks of said rivets While dissipating theheat from said shanks by cooling the same, and thereafter heading saidrivet-s so as to hot forge said heads over and into said piece.

2. The method of assembling metal articles by electric riveting whichcomprises positioning a plurality of metal rivets in a metal piece,passing electric current through the heads of said rivets and throughsaid piece, bringing electrodes into contact with said heads so as toheat said heads locally without substantially heating the shanks of saidrivets While dissipating the heat from said shanks by keeping the samein contact with a coolng medium, and thereafter heading said rivets soas to hot forge said heads over and into said piece.

3. The method of assembling metal articles by electric riveting whichcomprises positioning a plurality of steel rivets in a metal piece,passing electric current through the heads of said rivets and throughsaid piece so as to heat the heads locally without substantially heating,the shanks of Said rivets whle dissipating the heat from said shanks bykeeping the same in contact with Water, and thereafter heading saidrivets So as to hot forge said heads over and into said piece.

4. The method of assembling metal articles by electric riveting whichcomprises posi- `tioning a plurality of steel rivets in a metal piece,passing electric current through the heads of said rivets and throughsaid piece, bring'ng electrodes into -contact with said heads so as toheat said heads locally Without substantially heating the shanks of saidrivets While preventing said shanks from becoming heated to an annealingtemperature by keeping the same in contact With a cooling medium, andthereafter heading said rivets so as to hot forge said heads over andinto said piece.

In testimony whereof, I have signed my name to this specification this15th day of January, 1921.

f FRANK P. KOBERT.

